The Norwegian registry for spine surgery (NORspine): cohort profile.

PURPOSE: To review and describe the development, methods and cohort of the lumbosacral part of the Norwegian registry for spine surgery (NORspine). METHODS: NORspine was established in 2007. It is government funded, covers all providers and captures consecutive cases undergoing operations for degenerative disorders. Patients' participation is voluntary and requires informed consent. A set of baseline-, process- and outcome-variables (3 and 12 months) recommended by the International Consortium for Health Outcome Measurement is reported by surgeons and patients. The main outcome is the Oswestry disability index (ODI) at 12 months. RESULTS: We show satisfactory data quality assessed by completeness, timeliness, accuracy, relevance and comparability. The coverage rate has been 100% since 2016 and the capture rate has increased to 74% in 2021. The cohort consists of 60,647 (47.6% women) cases with mean age 55.7 years, registered during the years 2007 through 2021. The proportions > 70 years and with an American Society of Anaesthesiologists' Physical Classification System (ASA) score > II has increased gradually to 26.1% and 19.3%, respectively. Mean ODI at baseline was 43.0 (standard deviation 17.3). Most cases were operated with decompression for disc herniation (n = 26,557, 43.8%) or spinal stenosis (n = 26,545, 43.8%), and 7417 (12.2%) with additional or primary fusion. The response rate at 12 months follow-up was 71.6%. CONCLUSION: NORspine is a well-designed population-based comprehensive national clinical quality registry. The register's methods ensure appropriate data for quality surveillance and improvement, and research.

The Norwegian degenerative spondylolisthesis and spinal stenosis (NORDSTEN) study: study overview, organization structure and study population.

PURPOSE: To provide an overview of the The Norwegian Degenerative spondylolisthesis and spinal stenosis (NORDSTEN)-study and the organizational structure, and to evaluate the study population. METHODS: The NORDSTEN is a multicentre study with 10 year follow-up, conducted at 18 public hospitals. NORDSTEN includes three studies: (1) The randomized spinal stenosis trial comparing the impact of three different decompression techniques; (2) the randomized degenerative spondylolisthesis trial investigating whether decompression surgery alone is as good as decompression with instrumented fusion; (3) the observational cohort tracking the natural course of LSS in patients without planned surgical treatment. A range of clinical and radiological data are collected at defined time points. To administer, guide, monitor and assist the surgical units and the researchers involved, the NORDSTEN national project organization was established. Corresponding clinical data from the Norwegian Registry for Spine Surgery (NORspine) were used to assess if the randomized NORDSTEN-population at baseline was representative for LSS patients treated in routine surgical practice. RESULTS: A total of 988 LSS patients with or without spondylolistheses were included from 2014 to 2018. The clinical trials did not find any difference in the efficacy of the surgical methods evaluated. The NORDSTEN patients were similar to those being consecutively operated at the same hospitals and reported to the NORspine during the same time period. CONCLUSION: The NORDSTEN study provides opportunity to investigate clinical course of LSS with or without surgical interventions. The NORDSTEN-study population were similar to LSS patients treated in routine surgical practice, supporting the external validity of previously published results. TRIAL REGISTRATION: ClinicalTrials.gov; NCT02007083 10/12/2013, NCT02051374 31/01/2014 and NCT03562936 20/06/2018.

Characteristics and outcomes of patients who did not respond to a national spine surgery registry.

BACKGROUND: Loss to follow-up may bias outcome assessments in medical registries. This cohort study aimed to analyze and compare patients who failed to respond with those that responded to the Norwegian Registry for Spine Surgery (NORspine). METHODS: We analyzed a cohort of 474 consecutive patients operated for lumbar spinal stenosis at four public hospitals in Norway during a two-year period. These patients reported sociodemographic data, preoperative symptoms, and Oswestry Disability Index (ODI), numerical rating scales (NRS) for back and leg pain to NORspine at baseline and 12 months postoperatively. We contacted all patients who did not respond to NORspine after 12 months. Those who responded were termed responsive non-respondents and compared to 12 months respondents. RESULTS: One hundred forty (30%) did not respond to NORspine 12 months after surgery and 123 were available for additional follow-up. Sixty-four of the 123 non-respondents (52%) responded to a cross-sectional survey done at a median of 50 (36-64) months after surgery. At baseline, non-respondents were younger 63 (SD 11.7) vs. 68 (SD 9.9) years (mean difference (95% CI) 4.7 years (2.6 to 6.7); p = < 0.001) and more frequently smokers 41 (30%) vs. 70 (21%) RR (95%CI) = 1.40 (1.01 to 1.95); p = 0.044. There were no other relevant differences in other sociodemographic variables or preoperative symptoms. We found no differences in the effect of surgery on non-respondents vs. respondents (ODI (SD) = 28.2 (19.9) vs. 25.2 (18.9), MD (95%CI) = 3.0 ( -2.1 to 8.1); p = 0.250). CONCLUSION: We found that 30% of patients did not respond to NORspine at 12 months after spine surgery. Non-respondents were somewhat younger and smoked more frequently than respondents; however, there were no differences in patient-reported outcome measures. Our findings suggest that attrition bias in NORspine was random and due to non-modifiable factors.

Anterior surgical treatment for cervical degenerative radiculopathy: a prediction model for non-success.

PURPOSE: By using data from the Norwegian Registry for Spine Surgery, we wanted to develop and validate prediction models for non-success in patients operated with anterior surgical techniques for cervical degenerative radiculopathy (CDR). METHODS: This is a multicentre longitudinal study of 2022 patients undergoing CDR surgery and followed for 12 months to find prognostic models for non-success in neck disability and arm pain using multivariable logistic regression analysis. Model performance was evaluated by area under the receiver operating characteristic curve (AUC) and a calibration test. Internal validation by bootstrapping re-sampling with 1000 repetitions was applied to correct for over-optimism. The clinical usefulness of the neck disability model was explored by developing a risk matrix for individual case examples. RESULTS: Thirty-eight percent of patients experienced non-success in neck disability and 35% in arm pain. Loss to follow-up was 35% for both groups. Predictors for non-success in neck disability were high physical demands in work, low level of education, pending litigation, previous neck surgery, long duration of arm pain, medium-to-high baseline disability score and presence of anxiety/depression. AUC was 0.78 (95% CI, 0.75, 0.82). For the arm pain model, all predictors for non-success in neck disability, except for anxiety/depression, were found to be significant in addition to foreign mother tongue, smoking and medium-to-high baseline arm pain. AUC was 0.68 (95% CI, 0.64, 0.72). CONCLUSION: The neck disability model showed high discriminative performance, whereas the arm pain model was shown to be acceptable. Based upon the models, individualized risk estimates can be made and applied in shared decision-making with patients referred for surgical assessment.

Non-respondents do not bias outcome assessment after cervical spine surgery: a multicenter observational study from the Norwegian registry for spine surgery (NORspine).

BACKGROUND: The Norwegian registry for spine surgery (NORspine) is a national clinical quality registry which has recorded more than 10,000 operations for degenerative conditions of the cervical spine since 2012. Registries are large observational cohorts, at risk for attrition bias. We therefore aimed to examine whether clinical outcomes differed between respondents and non-respondents to standardized questionnaire-based 12-month follow-up. METHODS: All eight public and private providers of cervical spine surgery in Norway report to NORspine. We included 334 consecutive patients who were registered with surgical treatment of degenerative conditions in the cervical spine in 2018 and did a retrospective analysis of prospectively collected register data and data on non-respondents' outcomes collected by telephone interviews. The primary outcome measure was patient-reported change in arm pain assessed with the numeric rating scale (NRS). Secondary outcome measures were change in neck pain assessed with the NRS, change in health-related quality of life assessed with EuroQol 5 Dimensions (EQ-5D), and patients' perceived benefit of the operation assessed by the Global Perceived Effect (GPE) scale. RESULTS: At baseline, there were few and small differences between the 238 (71.3%) respondents and the 96 (28.7%) non-respondents. We reached 76 (79.2%) non-respondents by telephone, and 63 (65.6%) consented to an interview. There was no statistically significant difference between groups in change in NRS score for arm pain (3.26 (95% CI 2.84 to 3.69) points for respondents and 2.77 (1.92 to 3.63) points for telephone interviewees) or any of the secondary outcome measures. CONCLUSIONS: The results indicate that patients lost to follow-up were missing at random. Analyses of outcomes based on data from respondents can be considered representative for the complete register cohort, if patient characteristics associated with attrition are controlled for.

Accuracy and agreement of national spine register data for 474 patients compared to corresponding electronic patient records.

PURPOSE: Data quality is essential for all types of research, including health registers. However, data quality is rarely reported. We aimed to assess the accuracy of data in a national spine register (NORspine) and its agreement with corresponding data in electronic patient records (EPR). METHODS: We compared data in NORspine registry against data in (EPR) for 474 patients operated for spinal stenosis in 2015 and 2016 at four public hospitals, using EPR as the gold standard. We assessed accuracy using the proportion correctly classified (PCC) and sensitivity. Agreement was quantified using Kappa statistics or interaclass correlation coefficient (ICC). RESULTS: The mean age (SD) was 66 (11) years, and 54% were females. Compared to EPR, surgeon-reported perioperative complications displayed weak agreement (kappa (95% CI) = 0.51 (0.33-0.69)), PCC of 96%, and a sensitivity (95% CI) of 40% (23-58%). ASA classification had a moderate agreement (kappa (95%CI) = 0.73 (0.66-0.80)). Comorbidities were underreported in NORspine. Perioperative details had strong to excellent agreements (kappa (95% CI) ranging from 0.76 ( 0.68-0.84) to 0.98 (0.95-1.00)), PCCs between 93% and 99% and sensitivities (95% CI) between 92% (0.84-1.00%) and 99% (0.98-1.00%). Patient-reported variables (height, weight, smoking) had excellent agreements (kappa (95% CI) between 0.93 (0.89-0.97) and 0.99 (0.98-0.99)). CONCLUSION: Compared to electronic patient records, NORspine displayed weak agreement for perioperative complications, moderate agreement for ASA classification, strong agreement for perioperative details, and excellent agreement for height, weight, and smoking. NORspine underreported perioperative complications and comorbidities when compared to EPRs. Patient-recorded data were more accurate and should be preferred when available.

Surgery for degenerative cervical myelopathy in the elderly: a nationwide registry-based observational study with patient-reported outcomes.

BACKGROUND: The aim of this study was to investigate whether clinical outcomes in patients aged ≥ 70 undergoing decompressive surgery for degenerative cervical myelopathy (DCM) differ from those of younger patients (50-70 years) at 1 year. METHODS: Data were obtained from the Norwegian Registry for Spine Surgery (NORspine). Among 651 patients included, 177 (27.2%) were ≥ 70 years old. The primary outcome was change in the Neck Disability Index (NDI). Secondary outcomes were changes in the European Myelopathy Score (EMS), quality of life (EuroQoL EQ-5D), numeric rating scales (NRS) for headache, neck pain, and arm pain, and complications. RESULTS: Significant improvements in all patient-reported outcomes (PROMs) were detected for both age cohorts at 1 year. For the two age cohorts combined, there was a statistically significant improvement in the NDI score (mean 9.2, 95% CI 7.7 to 10.6, P < 0.001). There were no differences between age cohorts in mean change of NDI (- 8.9 vs. - 10.1, P = 0.48), EQ-5D (0.13 vs. 0.17, P = 0.37), or NRS pain scores, but elderly patients experienced a larger improvement in EMS (0.7 vs. 1.3, P = 0.02). A total of 74 patients (15.6%) in the younger cohort and 43 patients (24.3%) in the older cohort experienced complications or adverse effects within 3 months of surgery, mainly urinary and respiratory tract infections. CONCLUSION: Surgery for DCM was associated with significant improvement across a wide range of PROMs for both younger and elderly patients. Surgery for DCM should not be denied based on age alone.

Surgery for degenerative cervical myelopathy in patients with rheumatoid arthritis and ankylosing spondylitis: a nationwide registry-based study with patient-reported outcomes.

PURPOSE: To compare patient-reported outcomes (PROMs) following surgery for degenerative cervical myelopathy (DCM) among patients with rheumatoid arthritis (RA) or ankylosing spondylitis (AS) versus those without rheumatic diseases. METHODS: Data were obtained from the Norwegian Registry for Spine Surgery. The primary outcome was change in the Neck Disability Index (NDI) at 1 year. Secondary endpoints included the European Myelopathy Score (EMS), quality of life (EuroQoL-5D [EQ-5D]), numeric rating scales (NRS) for headache, neck pain, and arm pain, and complications. RESULTS: Among 905 participants operated between 2012 and 2018, 35 had RA or AS. There were significant improvements in all PROMs at 1 year and no statistically significant difference between the cohorts in mean change in NDI (- 0.64, 95% CI - 8.1 to 6.8, P = .372), EQ-5D (0.10, 95% CI - 0.04 to 0.24, P = .168), NRS neck pain (- 0.8, 95% CI - 2.0 to 0.4, P = .210), NRS arm pain (- 0.6, 95% CI - 1.9 to 0.7, P = .351), and NRS headache (- 0.5, 95% CI - 1.7 to 0.8, P = .460). DISCUSSION AND CONCLUSION: Our study adds to the limited available evidence that surgical treatment cannot only arrest further progression of myelopathy but also improve functional status, neurological outcomes, and quality of life in patients with rheumatic disease.

Effect of Spinal Cord Burst Stimulation vs Placebo Stimulation on Disability in Patients With Chronic Radicular Pain After Lumbar Spine Surgery: A Randomized Clinical Trial.

Importance: The use of spinal cord stimulation for chronic pain after lumbar spine surgery is increasing, yet rigorous evidence of its efficacy is lacking. Objective: To investigate the efficacy of spinal cord burst stimulation, which involves the placement of an implantable pulse generator connected to electrodes with leads that travel into the epidural space posterior to the spinal cord dorsal columns, in patients with chronic radiculopathy after surgery for degenerative lumbar spine disorders. Design, Setting, and Participants: This placebo-controlled, crossover, randomized clinical trial in 50 patients was conducted at St Olavs University Hospital in Norway, with study enrollment from September 5, 2018, through April 28, 2021. The date of final follow-up was May 20, 2022. Interventions: Patients underwent two 3-month periods with spinal cord burst stimulation and two 3-month periods with placebo stimulation in a randomized order. Burst stimulation consisted of closely spaced, high-frequency electrical stimuli delivered to the spinal cord. The stimulus consisted of a 40-Hz burst mode of constant-current stimuli with 4 spikes per burst and an amplitude corresponding to 50% to 70% of the paresthesia perception threshold. Main Outcomes and Measures: The primary outcome was difference in change from baseline in the self-reported Oswestry Disability Index (ODI; range, 0 points [no disability] to 100 points [maximum disability]; the minimal clinically important difference was 10 points) score between periods with burst stimulation and placebo stimulation. The secondary outcomes were leg and back pain, quality of life, physical activity levels, and adverse events. Results: Among 50 patients who were randomized (mean age, 52.2 [SD, 9.9] years; 27 [54%] were women), 47 (94%) had at least 1 follow-up ODI score and 42 (84%) completed all stimulation randomization periods and ODI measurements. The mean ODI score at baseline was 44.7 points and the mean changes in ODI score were -10.6 points for the burst stimulation periods and -9.3 points for the placebo stimulation periods, resulting in a mean between-group difference of -1.3 points (95% CI, -3.9 to 1.3 points; P = .32). None of the prespecified secondary outcomes showed a significant difference. Nine patients (18%) experienced adverse events, including 4 (8%) who required surgical revision of the implanted system. Conclusions and Relevance: Among patients with chronic radicular pain after lumbar spine surgery, spinal cord burst stimulation, compared with placebo stimulation, after placement of a spinal cord stimulator resulted in no significant difference in the change from baseline in self-reported back pain-related disability. Trial Registration: ClinicalTrials.gov Identifier: NCT03546738.

A prognostic model for failure and worsening after lumbar microdiscectomy: a multicenter study from the Norwegian Registry for Spine Surgery.

OBJECTIVE: To develop a prognostic model for failure and worsening 1 year after surgery for lumbar disc herniation. METHODS: This multicenter cohort study included 11,081 patients operated with lumbar microdiscectomy, registered at the Norwegian Registry for Spine Surgery. Follow-up was 1 year. Uni- and multivariate logistic regression analyses were used to assess potential prognostic factors for previously defined cut-offs for failure and worsening on the Oswestry Disability Index scores 12 months after surgery. Since the cut-offs for failure and worsening are different for patients with low, moderate, and high baseline ODI scores, the multivariate analyses were run separately for these subgroups. Data were split into a training (70%) and a validation set (30%). The model was developed in the training set and tested in the validation set. A prediction (%) of an outcome was calculated for each patient in a risk matrix. RESULTS: The prognostic model produced six risk matrices based on three baseline ODI ranges (low, medium, and high) and two outcomes (failure and worsening), each containing 7 to 11 prognostic factors. Model discrimination and calibration were acceptable. The estimated preoperative probabilities ranged from 3 to 94% for failure and from 1 to 72% for worsening in our validation cohort. CONCLUSION: We developed a prognostic model for failure and worsening 12 months after surgery for lumbar disc herniation. The model showed acceptable calibration and discrimination, and could be useful in assisting physicians and patients in clinical decision-making process prior to surgery.

Associations between utilization rates and patients' health: a study of spine surgery and patient-reported outcomes (EQ-5D and ODI).

BACKGROUND: A vast body of literature has documented regional variations in healthcare utilization rates. The extent to which such variations are "unwarranted" critically depends on whether there are corresponding variations in patients' needs. Using a unique medical registry, the current paper investigated any associations between utilization rates and patients' needs, as measured by two patient-reported outcome measures (PROMs). METHODS: This observational panel study merged patient-level data from the Norwegian Patient Registry (NPR), Statistics Norway, and the Norwegian Registry for Spine Surgery (NORspine) for individuals who received surgery for degenerative lumbar spine disorders in 2010-2015. NPR consists of hospital administration data. NORspine includes two PROMs: the generic health-related quality of life instrument EQ-5D and the disease-specific, health-related quality of life instrument Oswestry Disability Index (ODI). Measurements were assessed at baseline and at 3 and 12 months post-surgery and included a wide range of patient characteristics. Our case sample included 15,810 individuals. We analyzed all data using generalized estimating equations. RESULTS: Our results show that as treatment rates increase, patients have better health at baseline. Furthermore, increased treatment rates are associated with smaller health gain. CONCLUSION: The correlation between treatment rates and patients health indicate the presence of unwarranted variation in treatment rates for lumbar spine disorders.

Surgery for herniated lumbar disc in private vs public hospitals: A pragmatic comparative effectiveness study.

BACKGROUND: There is limited evidence on the comparative performance of private and public healthcare. Our aim was to compare outcomes following surgery for lumbar disc herniation (LDH) in private versus public hospitals. METHODS: Data were obtained from the Norwegian registry for spine surgery. Primary outcome was change in Oswestry disability index (ODI) 1 year after surgery. Secondary endpoints were quality of life (EuroQol EQ-5D), back and leg pain, complications, and duration of surgery and hospital stays. RESULTS: Among 5221 patients, 1728 in the private group and 3493 in the public group, 3624 (69.4%) completed 1-year follow-up. In the private group, mean improvement in ODI was 28.8 points vs 32.3 points in the public group (mean difference - 3.5, 95% CI - 5.0 to - 1.9; P for equivalence < 0.001). Equivalence was confirmed in a propensity-matched cohort and following mixed linear model analyses. There were differences in mean change between the groups for EQ-5D (mean difference - 0.05, 95% CI - 0.08 to - 0.02; P = 0.002) and back pain (mean difference - 0.2, 95% CI - 0.2, - 0.4 to - 0.004; P = 0.046), but after propensity matching, the groups did not differ. No difference was found between the two groups for leg pain. Complication rates was lower in the private group (4.5% vs 7.2%; P < 0.001), but after propensity matching, there was no difference. Patients operated in private clinics had shorter duration of surgery (48.4 vs 61.8 min) and hospital stay (0.7 vs 2.2 days). CONCLUSION: At 1 year, the effectiveness of surgery for LDH was equivalent in private and public hospitals.

Surgery for extraforaminal lumbar disc herniation: a single center comparative observational study.

BACKGROUND: Surgery on extraforaminal lumbar disc herniation (ELDH) is a commonly performed procedure. Operating on this type of herniation is known to come with more difficulties than on the frequently seen paramedian lumbar disc herniation (PLDH). However, no comparative data are available on the effectiveness and safety of this operation. We sought out to compare clinical outcomes at 1 year following surgery for ELDH and PLDH. METHODS: Data were collected through the Norwegian Registry for Spine Surgery (NORspine). The primary outcome measure was change at 1 year in the Oswestry Disability Index (ODI). Secondary outcome measures were quality of life measured with EuroQol 5 dimensions (EQ-5D); and numeric rating scales (NRSs). RESULTS: Data of a total of 1750 patients were evaluated in this study, including 72 ELDH patients (4.1%). One year after surgery, there were no differences in any of the patient reported outcome measurements (PROMs) between the two groups. PLDH and ELDH patients experienced similar changes in ODI (- 30.92 vs. - 34.00, P = 0.325); EQ-5D (0.50 vs. 0.51, P = 0.859); NRS back (- 3.69 vs. - 3.83, P = 0.745); and NRS leg (- 4.69 vs. - 4.46, P = 0.607) after 1 year. The proportion of patients achieving a clinical success (defined as an ODI score of less than 20 points) at 1 year was similar in both groups (61.5% vs. 52.7%, P = 0.204). CONCLUSIONS: Patients operated for ELDH reported similar improvement after 1 year compared with patients operated for PLDH.

Effectiveness of surgery for sciatica with disc herniation is not substantially affected by differences in surgical incidences among three countries: results from the Danish, Swedish and Norwegian spine registries.

PURPOSE: Yearly incidence of surgery for symptomatic lumbar disc herniation varies and is 29/100,000 in Sweden, 46/100,000 in Denmark and 58/100,000 in Norway. This variation was used to study whether differences in surgical incidence were associated with differences in preoperative patient characteristics as well as patient-reported outcomes. METHODS: Data from the national spine registers in Sweden, Denmark and Norway during 2011-2013 were pooled, and 9965 individuals, aged 18-65 years, of which 6468 had one-year follow-up data, were included in the study. Both absolute and case-mix-adjusted comparisons of the primary outcome Oswestry Disability Index (ODI) and the secondary outcomes EQ-5D-3L, and Numerical Rating Scale (NRS) for leg and back pain were performed. Case-mix adjustment was done for baseline age, sex, BMI, smoking, co-morbidity, duration of leg pain and preoperative value of the dependent variable. RESULTS: Mean improvement in the outcome variables exceeded previously described minimal clinical important change in all countries. Mean (95% CI) final scores of ODI were 18 (17-18), 19 (18-20) and 15 (15-16) in Sweden, Denmark and Norway, respectively. Corresponding results of EQ-5D-3L were 0.74 (0.73-0.75), 0.73 (0.72-0.75) and 0.75 (0.74-0.76). Results of NRS leg and back pain behaved similarly. Case-mix adjustment did not alter the findings substantially. CONCLUSION: We found no clear association between incidence of surgery for lumbar disc herniation and preoperative patient characteristics as well as outcome, and the differences between the countries were lower than the minimal clinical important difference in all outcomes. These slides can be retrieved under Electronic Supplementary Material.

Criteria for failure and worsening after surgery for lumbar disc herniation: a multicenter observational study based on data from the Norwegian Registry for Spine Surgery.

PURPOSE: In clinical decision-making, it is crucial to discuss the probability of adverse outcomes with the patient. A large proportion of the outcomes are difficult to classify as either failure or success. Consequently, cutoff values in patient-reported outcome measures (PROMs) for "failure" and "worsening" are likely to be different from those of "non-success". The aim of this study was to identify dichotomous cutoffs for failure and worsening, 12 months after surgical treatment for lumbar disc herniation, in a large registry cohort. METHODS: A total of 6840 patients with lumbar disc herniation were operated and followed for 12 months, according to the standard protocol of the Norwegian Registry for Spine Surgery (NORspine). Patients reporting to be unchanged or worse on the Global Perceived Effectiveness (GPE) scale at 12-month follow-up were classified as "failure", and those considering themselves "worse" or "worse than ever" after surgery were classified as "worsening". These two dichotomous outcomes were used as anchors in analyses of receiver operating characteristics (ROC) to define cutoffs for failure and worsening on commonly used PROMs, namely, the Oswestry Disability Index (ODI), the EuroQuol 5D (EQ-5D), and Numerical Rating Scales (NRS) for back pain and leg pain. RESULTS: "Failure" after 12 months for each PROM, as an insufficient improvement from baseline, was (sensitivity and specificity): ODI change <13 (0.82, 0.82), ODI% change <33% (0.86, 0.86), ODI final raw score >25 (0.89, 0.81), NRS back-pain change <1.5 (0.74, 0.86), NRS back-pain % change <24 (0.85, 0.81), NRS back-pain final raw score >5.5 (0.81, 0.87), NRS leg-pain change <1.5 (0.81, 0.76), NRS leg-pain % change <39 (0.86, 0.81), NRS leg-pain final raw score >4.5 (0.91, 0.85), EQ-5D change <0.10 (0.76, 0.83), and EQ-5D final raw score >0.63 (0.81, 0.85). Both a final raw score >48 for the ODI and an NRS >7.5 were indicators for "worsening" after 12 months, with acceptable accuracy. CONCLUSION: The criteria with the highest accuracy for defining failure and worsening after surgery for lumbar disc herniation were an ODI percentage change score <33% for failure and a 12-month ODI raw score >48. These cutoffs can facilitate shared decision-making among doctors and patients, and improve quality assessment and comparison of clinical outcomes across surgical units. In addition to clinically relevant improvements, we propose that rates of failure and worsening should be included in reporting from clinical trials.

The effectiveness of decompression alone compared with additional fusion for lumbar spinal stenosis with degenerative spondylolisthesis: a pragmatic comparative non-inferiority observational study from the Norwegian Registry for Spine Surgery.

PURPOSE: To evaluate the effect of adding fusion to decompression in patients operated for lumbar spinal stenosis with a concomitant lumbar degenerative spondylolisthesis. METHODS: After propensity score matching, 260 patients operated with decompression and fusion and 260 patients operated with decompression alone were compared. Primary outcome measures were leg and back pain [Numeric Rating Scale (NRS), 0-10] and Oswestry Disability Index (ODI, 0-100) at 12 months. RESULTS: At 12-month follow-up, the fusion group rated their pain significantly lower than the decompression alone group [leg pain 3.0 and 3.6, respectively, mean difference -0.6, 95 % confidence interval (CI) -1.2 to -0.05, p = 0.03 and back pain 3.3 and 3.9, respectively, mean difference -0.6, 95 % CI -1.1 to -0.1, p = 0.02]. ODI was not significantly different between the groups (21.0 versus 23.3, mean difference -2.3, 95 % CI -5.8 to 1.1, p = 0.18). Seventy-four percent of the fusion group and 63 % of the decompression alone group achieved a clinically important improvement in back pain (difference in proportion of responders = 11 %, 95 % CI 2-20 %, p = 0.01), corresponding to a number needed to treat of 9 patients (95 % CI 5-50). There was no significant difference in responder rate for leg pain (74 and 67 %, respectively, difference 7 %, 95 % CI -1 to 16 %, p = 0.09) or for ODI (67 and 59 %, respectively, difference 8 %, 95 % CI 0-18 %, p = 0.06). The duration of surgery and hospital stay was longer for the fusion group (mean difference 68 min, 95 % CI 58-78, p < 0.01 and mean difference 4.2 days, 95 % CI 3.5-4.8, p < 0.01). CONCLUSION: In the present non-inferiority study, we cannot conclude that decompression alone is as good as decompression with additional fusion. However, the small differences in the groups' effect sizes suggest that a considerable number of patients can be treated with decompression alone. A challenge in future studies will be to find the best treatment option for each patient.

Risk factors for surgical site infections among 1,772 patients operated on for lumbar disc herniation: a multicentre observational registry-based study.

BACKGROUND: There are no previous studies evaluating risk factors for surgical site infections (SSIs) and the effectiveness of prophylactic antibiotic treatment (PAT), specifically for patients operated on for lumbar disc herniation. METHOD: This observational multicentre study comprises a cohort of 1,772 consecutive patients operated on for lumbar disc herniation without laminectomy or fusion at 23 different surgical units in Norway. The patients were interviewed about SSIs according to a standardised questionnaire at 3 months' follow-up. RESULTS: Three months after surgery, 2.3% of the patients had an SSI. Only no PAT (OR = 5.3, 95% CI = 2.2-12.7, p< 0.001) and longer duration of surgery than the mean time (68 min) (OR = 2.8, 95% CI = 1.2-6.6, p = 0.02) were identified as independent risk factors for SSI. Numbers needed to have PAT to avoid one SSI was 43. CONCLUSIONS: In summary, this study clearly lends support to the use of PAT in surgery for lumbar disc herniation. Senior surgeons assisting inexperienced colleagues to avoid prolonged duration of surgery could also reduce the occurrence of SSI.

Lumbar microdiscectomy for sciatica in adolescents: a multicentre observational registry-based study.

BACKGROUND: Lumbar disc herniation (LDH) is rare in the adolescent population. Factors predisposing to LDH in adolescents differ from adults with more cases being related to trauma or structural malformations. Further, there are limited data on patient-reported outcomes after lumbar microdiscectomy in adolescents. Our aim was to compare clinical outcomes at 1 year following single-level lumbar microdiscectomy in adolescents (13-19 years old) compared to younger adults (20-50 years old) with LDH. METHODS: Data were collected through the Norwegian Registry for Spine Surgery. Patients were eligible if they had radiculopathy due to LDH, underwent single-level lumbar microdiscectomy between January 2007 and May 2014, and were between 13 and 50 years old at time of surgery. The primary endpoint was change in Oswestry Disability Index (ODI) 1 year after surgery. Secondary endpoints were generic quality of life (EuroQol five dimensions [EQ-5D]), back pain numerical rating scale (NRS), leg pain NRS and complications. RESULTS: A total of 3,245 patients were included (97 patients 13-19 years old and 3,148 patients 20-50 years old). A significant improvement in ODI was observed for the whole population, but there was no difference between groups (0.6; 95% CI, -4.5 to 5.8; p = 0.811). There were no differences between groups concerning EQ-5D (-0.04; 95% CI, -0.15 to 0.07; p = 0.442), back pain NRS (-0.4; 95% CI, -1.2 to 0.4; p = 0.279), leg pain NRS (-0.4; 95% CI, -1.2 to 0.5; p = 0.374) or perioperative complications (1.0% for adolescents, 5.1% for adults, p = 0.072). CONCLUSIONS: The effectiveness and safety of single-level microdiscectomy are similar in adolescents and the adult population at 1-year follow-up.

The use of surgery for cervical degenerative disease in Norway in the period 2008-2014 : A population-based study of 6511 procedures.

BACKGROUND: The incidence rate of surgical treatment of cervical degenerative diseases (CDD) has increased in the USA and a large geographic variation has been shown. Little is known about such rates in Scandinavia and Europe. The aim of this population-based study was to (1) investigate annual incidence rates of operations performed in Norway, (2) to compare trends and variations in rates for surgical indications with and without myelopathy, and (3) to compare variations in the use of surgery between residential areas. METHODS: Patients operated for CDD and recorded in the Norwegian Patient Registry from 2008 to 2014 were evaluated according to residential areas (resident county and Regional Health Authority (RHA) area), age, gender, treating hospital, and whether myelopathy was present or not. Surgical rates were adjusted for age and gender. Data from private health care were also included. RESULTS: The annual surgical rates increased by 74.1 % from 2008 to 2014 (12.5/100,000 inhabitants). The largest increase was for surgical treatment of radiculopathy, 86.5 %. Surgical rates for CDD varied in 2014 with a ratio of 1.5 between the highest and lowest RHA and with a ratio of 2.5 between the different residential counties within one RHA. The treatment rates for myelopathy were relatively stable over time, but showed an increase of 2.1/100,000 (44.6 %) from 2013 to 2014. CONCLUSIONS: Our study shows that the rate of surgical treatment for radiculopathy due to CDD has increased substantially from 2008 to 2014 for all RHAs in Norway. The incidence rate for surgical treatment of myelopathy was more stable. An unexplained and moderate geographic variation was found.